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221 Cards in this Set
- Front
- Back
ecological diversity
|
same thing as species diversity
*NOT biodiversity!!* |
|
biodiversity
|
the variety of life and its processes (variety of living organisms) ----
-----INCLUDES their genetic differences & the communities/ecosystems they occur in NOT ecological or species diversity |
|
species diversity
|
includes species richness & evenness
=ecological diversity |
|
species richness
|
number of species present in given area
*simple count* |
|
species evenness
|
distribution of individuals in total species in given area
[relative abundance of species in community] *calculated index* |
|
communities are ________
|
ARBITRARY
(changing) |
|
stratification
(leads to pattern diversity) |
local-scale VERTICAL LAYERING
of vegetation, soil, biota, systems, intertidal, etc. |
|
zonation
(leads to pattern diversity) |
regional-scale patterns
**LIFE ZONES** |
|
temporal
(leads to pattern diversity) |
period in time
|
|
trophic
(leads to pattern diversity) |
network organization of food webs
|
|
reproductive
(leads to pattern diversity) |
parent - offspring patterns
plant clones |
|
social
(leads to pattern diversity) |
flocks, herds, schools, etc
|
|
co-active
(leads to pattern diversity) |
patterns from competition, mutualism, antibiosis, etc
|
|
increase in stability =
increase in diversity |
increase in stability =
increase in diversity *when less diverse food chain, one species dying off can result in extinction of many more species* larger # of species -> more redundancy in system (species can be substituted) -> resiliance (can recover from disturbance) |
|
Diversity indexes:::
|
Simpsons
& Shannon-Weiner index |
|
Richness
& Evenness INCREASE WITH |
-ecological time time (ecological succession)
-evolutionary time (community evolution) -from poles to equator (latitudinal diversity gradiant) -in warm / moist enviros |
|
Richness
& Evenness DECREASE WITH |
-rigorous (dry / cold enviros)
-with disturbances |
|
alpha diversity
(diversity is SCALE / level dependent!) |
WITHIN habitats
|
|
beta diversity
(diversity is SCALE / level dependent!) |
BETWEEN habitats
|
|
gamma diveristy
(diversity is SCALE / level dependent!) |
diversity of landcape scale areas
|
|
the living component of an ecosystem?
|
COMMUNITY
|
|
global sum of communities?
|
THE BIOSPHERE
|
|
Communities are structured by:
|
SYMBIOSIS (+, -, 0)
|
|
Symbiosis leads to
|
exchanges of materials in an ecosystem
|
|
Competition leads to
|
NICHE structure of communities
|
|
over time _______ increases
|
diversity (richness / evenness)
|
|
interspecific competition w/i communities
leads to |
divergence of species
*evolution of biodiversity* |
|
community ecology is part of the PROCESSES and PRODUCTS of evolution
|
heritable variation
+ overpopulation (pop ecology) + competition (pop & comm ecology) ------------------------ natural selection |
|
smallest unit of ecology?
|
individuals
(individual organisms) |
|
population
|
all the individuals of a species w/ potential to interbreed
(in a particular area at a specific time) --time and space are implied |
|
"population size"
|
number of individuals
(street term pop = # of ind as well) |
|
DISTRIBUTION
of population |
occurance of population in a space
*DESCRIBES SPATIAL LOCATION, based on presence, absence of ind* (due to limits) *biogeographic concept* -often discontinuous -area including all ind of pop = geographic range -influenced by limits --ind's have to be w/i range of tolerance |
|
metapopulation
|
subpopulations (local populations) that can interact with eachother
metapopulation MUST have: 1)descrete habitat patches 2)substantial risk of extinction 3)migration & recolonization after local extinction 4)asynchronous dynamics *balance between extinction & recolonization of empty habitat patches |
|
population density
|
individuals / unit area
or individuals / volume *sessile - divide into quadrants *mobile - mark-recapture method |
|
population dispersion
|
spatial arrangment of individuals within a population
(how individuals are spaced out) 1)RANDOM 2)CLUMPED [contagious] 3)UNIFORM [hyperdispersed] |
|
random dispersion
|
no intraspecific interaction
least common |
|
clumped [contagious]dispersion
|
+ social interactions,
maternal care most common |
|
uniform [hyperdispersed] dispersion
|
territoriality
|
|
age/sex structure
(age/sex distribution) |
relative # of individuals of each age segregated by sex
|
|
population growth =
|
(birth + immigration)
- (death + emmigration) AKA recruitment rate - loss rate = pop growth rate ***rate = change / time |
|
exponential growth
|
growth at a fixed RATE (%/yr)
(NOT a fixed amt) *unregulated populations* |
|
pop growth curves
|
show
change in pop size over time |
|
"r" on pop curve
|
= rate of increase
= biotic potential = slope of curve = change N / change t (time) |
|
if pop grows exponentially, doubling daily and is completely full on 30th day... on what day is it half full?
|
29th day... last day of doubling before full
*remember exponential growth means DOUBLING everytime!!!* |
|
"Survivorship"
|
age specific death rate
(probability of an individuals death at a given age) *shown as species specific survivorship curve [type I-human, type II-robin, type III-oyster]* *curve derived from life table* ***REFLECTS species Reproductive Strategy*** |
|
limiting factors
(of population growth) |
restrain exponential pop growth... slowing growth rate down
**may level off at carrying capacity** |
|
carrying capacity
|
max population of species an enviro can sustain
*based on resources, NOT a feature of a pop* *measured by individuals (a pop size)* |
|
logistic growth curve
|
initial exponential growth, slowing, then stabilizing at carrying capacity (K)
*S curve* |
|
logistic growth equation
|
dN / dt = rN (K - N/K)
|
|
environmental resistence (k)
|
the sum of factors that keep the observed pop increase below the theoretical max increase
k = r-max - r-observed |
|
Density independent controls
(limiting populations) |
not controlled in respect of initial densisty
[100 yr flood drowns all beavers, whether pop is 5 or 500] *usually due to abiotic factors [flood, fire, frost] |
|
Density dependent regulation
(limiting populations) |
how intense the regulatory mechanism is proportional to pop size
(larger the pop the larger the regulatory effect) *NEGATIVE FEEDBACK LOOP* *usually due to biotic factors: -food -nesting sites / territoriality -competition -predation |
|
populations limited by two types: (in addition to density dependent and density independent controls)
1)INTRINSIC 2)EXTRINSIC |
1)INTRINSIC
-pop regulates itself [territoriality, competition for mates] 2)EXTRINSIC: -pop controlled by outside forces [food, nesting sites, predation] |
|
"territory"
|
portion of home-range defended against individuals of the SAME species
*DO NOT OVERLAP* |
|
"home-range"
|
area through which individual moves during usual round of activities
*OVERLAP* (time frame may be needed to distinguish home range -- daily v monthly, etc) -associated with 1)dispersal (ONE WAY movement from place of birth to place of reproduction. PERMANENT) 2)migration (movement, often seasonal, from one place to another AND BACK. a -> b -> a. often seasonal change in home range.) |
|
distinction between
"home-range" and "territory" MADE BY |
W. H. BURT
|
|
DISPERSAL v MIGRATION
change in Home-Range |
1)dispersal
(ONE WAY movement from place of birth to place of reproduction. PERMANENT) 2)migration (movement, often seasonal, from one place to another AND BACK. a -> b -> a. often seasonal change in home range.) |
|
all mechanisms that influence pop size::
|
1) density-dependent v density-independent factors
2) intrinsic v extrinsic factors 3) birth-rate v death-rate mechanisms [b - d = r] |
|
"biotic potential"
|
potential growth rate (r)
of a particular species (innate reproductive capacity) (rate of natural increase) **HIGH r = species producing a lot of young (insects/fish/plants) **LOW r = mammals & birds (produce few young / time interval) |
|
High v Low "r"
("r" = potential growth rate) |
HIGH "r" = species that produce a lot of young (fish/insects/plants)
LOW "r" = few young / time interval (mammals/birds) ****DIFFERENT STRATEGIES***** |
|
"life history"
AKA "reproductive strategy" |
a species general pattern of reproduction
*how many offspring does it take to acheive fitness?* *ie success in becoming a grandparent... **an ind. getting genes into the gene pool of the next generation |
|
r-strategists
|
-many offspring
-little parental care -small body size -fast growth rate (comes from logistic curve... pops can potentially grow fast, have high r) |
|
K-strategists
|
-few offspring
-high parental care -large body size -slow growth rate (comes from logistic curve... some pops reproduce so they tend to stabilize near K.) |
|
"demography"
|
human population ecology
|
|
High v Low "r"
("r" = potential growth rate) |
HIGH "r" = species that produce a lot of young (fish/insects/plants)
LOW "r" = few young / time interval (mammals/birds) ****DIFFERENT STRATEGIES***** |
|
"life history"
AKA "reproductive strategy" |
a species general pattern of reproduction
*how many offspring does it take to acheive fitness?* *ie success in becoming a grandparent... **an ind. getting genes into the gene pool of the next generation |
|
r-strategists
|
-many offspring
-little parental care -small body size -fast growth rate (comes from logistic curve... pops can potentially grow fast, have high r) |
|
K-strategists
|
-few offspring
-high parental care -large body size -slow growth rate (comes from logistic curve... some pops reproduce so they tend to stabilize near K.) |
|
"demography"
|
human population ecology
|
|
human populations often distort ecosystems by amensalism
|
amensalism = when one species is harmed and the other is unaffected
|
|
distribution of human population?
(peculiarity) |
GLOBAL
-widest of any vertebrate |
|
worldwide density of human pop?
(peculiarity) |
highest of any megavertebrate
127 / sq. mile |
|
dispersion of human pop?
(peculiarity) |
highly contagious
(large human cities = largest known sums of any terrestrial vertebrate) |
|
carrying capacity (k) for humans has to do with:
|
economics, ethics, peer pressure, cultures
|
|
Poverty is POSITIVELY correlated with pop. growth rates
|
(lower education, higher growth rates)
|
|
Human's survivorship curve?
|
Type III
(CONVEX) |
|
Human growth rate curve is:
|
exponential as of now
|
|
why the pop boom?
|
advances in public health
(people began to live longer on average) |
|
fertility rate is POSITIVELY correlated with pop density
|
higher density = higher reproductive output
*no apparent intrinsic, density-dependent regulator.... no reproductive strategy* --Probably due to the fact that k has been expanded by cultural advances thru history |
|
human age/sex diagram?
(peculiarity) |
long post-reproductive life span
|
|
carrying capacity of humans?
(peculiarity) |
no apparent k so far
(humans fit k-strategists description but culture keeps pushing k up) |
|
times in human history that k has been raised:
|
1)Paleolithic Revolution
-taming of fire -expanded geographic range 2)Neolithic Revolution -agriculture 3)1st Industrial Revolution -steam engine -fossil fuels 4)Advanced Industrial Revolution -electric power -combustion engine (technology, tool-making, agriculture, & industrialization expanded carrying capacity) |
|
cultural influences affecting human pop growth?
(peculiarity) |
education correlated with TFR
*more education = fewer children* *family planning = fewer children* |
|
human population growth rate has fallen since ___?
|
1960s
(but still a + growth rate, and resource demand still rising) |
|
(increasing population) x (increasing resource demand / capita)
====================== |
(increasing population) x (increasing resource demand / capita)
====================== INCREASING IMPACT ON THE ECOSPHERE |
|
"IPAT" model
|
I = P x A x T
Impact = (Population)(Affluence)(Technology) |
|
Total Human Population? (#)
|
6.555 BILLION
|
|
Annual % growth rate of human pop:
|
1.2 %
|
|
Doubling Time of human pop?
|
58 Years
|
|
Doubling Time
EQUATION |
70 / % rate of growth
======================= Doubling Time (bacteria doubling time growing at 5% per hour = 70 / 5 = 14 Hours) |
|
ecological footprint
|
= population x resource demand
|
|
population density
v ecological density |
pop density :
individuals / unit area individuals / volume ecological density: #s / area of suitable habitat (expresses how many ppl per resource base... human impact on the ecosphere) |
|
4 principle stress factors
for pop growth |
1) youth bulge
2) rapid urban growth 3)competition for cropland / freshwater 4) HIV/ AIDS (death in prime of life) *most in africa* |
|
giga-people-bucks / area
|
pop x demand = people-bucks
people x bucks = giga-people-bucks giga-people-bucks / area = demand density = ecological footprint |
|
PATTERN implies
|
PROCESS (history)
we need the process to understand the pattern |
|
humans are immense force in ecosphere bc we are:
|
HUGE
NUMEROUS WARM (endotherms)...(endotherms are expensive |
|
E. O. Wilson
|
SOCIOBIOLOGY
|
|
Sociobiology includes
|
-evolutionary biology
-anthropology -ethology -comparative psychology -sociology -social psychology -population ecology |
|
opportunities for social evolution
|
-anti-predator defences
-increased competitive ability -increase foraging ability -cooperative predation -increased reproductive efficiency -increased survival at hatching -modification of physical enviro *schools of fish* |
|
communication implies:
|
transmitter
-->signal ---->receptor *channels of communication = visual mechanical chemical electrical heat |
|
Doubling Time
EQUATION |
70 / % rate of growth
======================= Doubling Time (bacteria doubling time growing at 5% per hour = 70 / 5 = 14 Hours) |
|
conservation ecology seeks to conserve
|
BIODIVERSITY
|
|
biodiversity
|
The variety of life and its processes;
variety of living organisms, genetic differences amoung them; the communities & ecosystems in which they occur -the variety of life and the patterns it forms -the sum of organisms, their genetic variability, historical relationships, & symbiotic interactions -a "progress report" on cosmic process of evolution -not a state but a process **Comprises all levels of integration (genes to proteins to geno/pheno to individuals & offspring to communities to landscapes to ecosystems to biosphere as whole) demands appreciation for evolution & ecology over space & time -a global inventory of species *not simply richness & evenness (or ecological/species diversity)* |
|
the sum of organisms, their genetic variability, historical relationships and symbiotic interactions =
|
BIODIVERSITY
|
|
most species that have ever been are extinct
|
but present day extinction rates seem unusually high
|
|
extinction caused by:
|
failure to adapt
(to: PREVIOUSLY: -climate change -volcanism -mountain building -disease -extra-terrestrial influences) (to: CURRENT: 1)HABITAT LOSS 2)pollution 3)exotic species 4)exploitation 5)disease) [failure to adapt to humans] |
|
how many mass extinctions in history?
|
5
we could be in the midst of the 6th |
|
conservation biology
|
applies principles of ecology, biogeography, pop. genetics, economics, sociology, anthropology, philosophy to MAINTAIN BIOLOGICAL DIVERSITY
study to maintain, protect, & restore life CONSERVATION GENETICS + CONSERVATION ECOLOGY = CONSERVATION BIOLOGY *APPLIED EVOLUTIONARY BIOLOGY* *theory of island biogeography important* (only ~ 20 years old) |
|
mass extinctions
(qualities) |
-global
-involve broad range of organisms -rapid |
|
people responsible for conservation biology
|
-victor shelford
-aldo leopold -charles elton -e. o. wilson (spokesman) -macarther (founding giants of ecology) |
|
# of species on an "island" represents
|
EQUILIBRIUM
between immigration & extinction -extinction varies w/island size -immigration varies w/distance from mainland |
|
island biography predicts
|
smaller islands farther from mainland = smaller biotas
|
|
SLOSS
|
single large or several small?
|
|
Goals of Conservation Biology
[by SOCIETY OF CONSERVATION BIOLOGY (SCB)] |
-protection, maintanence, restoration
-promotion -management -encouragement of sciences -education at all levels -promotion of all of the above |
|
leading cause of extinction?
|
HABITAT LoSS
(then pollution, exotic species, exploitation, & last-disease) |
|
if species are going extinct bc we're destroying their habitats THEN
|
we must focus on habitats and not just the species
*avoid human creation of islands |
|
organisms can be
1)unitary 2)modular |
1)unitary
-zygote -through sexual reproduction -genetically unique organism 2)modular -zygote develops into unit of construction (module) -then produces further similar modules -(most plants) -new shoots or suckers can remain attached or break off & live independently |
|
types of modules
|
1)genet
-individual tree/plant produced by sexual reproduction -arising from a zygote -genetic individual 2)ramet -can remain linked to parent genet or may seperate -possess same genetic comp as parent |
|
geographic range
|
area including entire pop of a species
-influenced by limits |
|
abundance
|
defines size
*the number of individuals in a population* FUNCTION OF: 1)density (#/unit area = crude density) 2)Distribution |
|
DISPERSION
(spatial arrangement wi a pop) 1)random 2)uniform 3)clumped |
1)RANDOM
-position of each is independent of others 2)UNIFORM -usually results from negative interaction [competition] 3)CLUMPED -MOST COMMON -results from suitable habitat in patches, social groups, plants that reproduce asexually (ramets extending from parent plant) |
|
age structure
|
proportion of individuals in different age classes
1)pre-reproductive 2)reproductive 3)post-reproductive *short lived organisms = short pre-reproductive period = high growth rate *long lived organsisms = long pre-repro period = slow growth rate (longer time span between generations **age pyramids are snapshots of age structure at pt in time --patterns of mortality & reproduction |
|
sex ratio of sexually reproducing organisms
& primary sex ratio (ratio at conception)? |
1:1
1:1 |
|
Life Table
|
age-specific account of mortality
displayed in 1) mortality curve 2)survivorship curve [type I, II, & III] |
|
cohort
|
group of ind born in same period of time
|
|
age-specific mortality rate
|
# ind died during given time interval / number alive at beginning of interval
|
|
dynamic life table
|
follows cohort from birth to death
[dynamic COMPOSIT life table follows ind born over several time periods not just one] |
|
time-specific life table
|
obtain distribution of age classes during single time period
--less accurate |
|
TYPE I
survivorship curve |
humans / mammals
-survival rate high thru life span w/ heavy mortality rate toward end -convex ) |
|
TYPE II
survivorship curve |
birds / rodents / reptiles
-survival rates don't vary w age -straight line |
|
TYPE III
survivorship curve |
oysters / fish
-mortality rates high early in life -concave ( |
|
Sociobiology
|
the study of social behavior
(sociality... the tendancy for interaction between members of the same species) -branch of population ecology |
|
"society"
|
group of individuals of same species organized in cooperative manner
|
|
sociality
[definition & advantages] |
the tendasncy for interaction amoung/between members of same species
HAS EVOLVED IN RESPONSE TO ENVIRO PRESSURES: 1)defense against predators: (flock of birds w/100 eyes v 1 bird w/2eyes) *flocks, herds, schools, etc* 2)modifies physical enviro: -air conditioned nests -heat generated from colony 3)foraging efficiency -mixed species of birds can group 4)reproductive functions -increasing genetic diversity 5)social protection of young -increases survival of young |
|
"communication"
in sociality |
an action by one ind that alters the probability of the behavior of another animal [not cause but alter]
-implies a SENDING ind (transmitter) and a RECEIVING ind (which may or may not respond) -social behavior depends on communication species communicate by making senders match their receptors |
|
Receivers
|
in complex organisms are transducers (converts input energy into output energy)
-once there's a receiver all thats needed is a sender (allowing a communicative link to be established) |
|
agonistic behavior
|
involves contest between 2 ind of the same species
-is cooperative *mothers aggresively protective over young* *status* *spacing* |
|
altruism
|
when ind endangers or destroys itself to benefit another
*a deer may endanger herself but save a full nest of young, thus increasing fitness* |
|
E O Wilson
|
brought together darwin and such to publish book on SOCIOLOGY
|
|
organic altruism
|
product of biological evolution
(NOT based on genetic self sacrifice) |
|
cultural altruism
|
a human peculiarity
product of cultural evolution, NOT biological evolution |
|
holocene
|
most recent geologic time interval
(present geological epoch) time since latest glacial maximum -an interval of increasing human predominance ("homogecene" due to increasing globalization |
|
homogenization may be self limiting
|
global climate change
-->resource exhaustion |
|
human population growth is not the issue...
|
the issue is
# of people x per capita demand for materials / energy (the human ecological footprint) |
|
human biomass
|
3.9% of global animal biomass
|
|
human's take __ annual production of entire biosphere
|
~ 25 - 40 %
|
|
energy used started dramatically increasing
|
@ early INDUSTRIAL
& further at advanced industrial & further at post industrial |
|
unique about the holocene epoch?
|
-rates of cultural evolution
-degree of dominance of single species -number of people x demand per person -oxidation of fossil fuels ->release of C into atmosphere ->cultural climate change -single species impacts ecosphere on geological scale -biogeochemical cycles -> anthrobiogeochemical cycles |
|
depletion curve for "stock limited" (non-renewable) resources
|
at peak (y sub p)
y sub 50 = year 50 % depleted beyond y50 price rises, scarcity increases *by HUBBERT* (came very close to actual oil depletion estimate) |
|
"population growth"
|
# of individuals increasing / decreasing with time
change in pop / change in time = (b-d)(pop)(time) |
|
open populations
|
immigation &/or emmigration occur
|
|
closed populations
|
movement in & out of populations does not occur
-no immigration or emmigration |
|
exponential pop growth
|
rate of pop change thru time
-characteristic of pop's inhabiting favorable enviros @ low pop densities |
|
crude birthrate
|
*birthrates expressed as births per 1000 population per unit time
(# of births over time period) / (estimated pop size at beginning of time period) * 1000 |
|
gross reproductive rate
|
sum of age-specific birth ratesof all age classes
-gives avg number of female offspring born to female over lifetime |
|
age-specific birthrates
|
avg number of female births per female at age x
|
|
fercundity table
|
aka fertility table
-uses survivorship from life table together with age specific BR's |
|
net reproductive rate
|
avg # of females that will be left during the lifetime of a newborn female
(on avg females replace themselves --produce one daughter |
|
demographic stochasticity
|
random (stochastic) variations in B & D rates occuring in a pop from year to year
|
|
environmental stochasticity
|
random variations in the enviro
(including annual variations in climate or natural disasters) that can directly influence B & D rates |
|
factors leading to pop extinction
|
1)D rate exceeding B rate
2)if enviro events exceed bounds of tolerance for species (droughts floods) 3)shortage of resources by enviro extremes or overexploitation 4)new species introduced 5)loss of habitat |
|
a small population's susceptability to extinction
|
1)small populations
-only a few ind -widely dispersed = hard to find mate -breakdown of social structures that species cooperate to mate, forage, defend -reduced genetic diversity -inbreeding (rare recessive deleted genes can become widely expressed) |
|
allee effect
|
decline in either reproduction or survival under conditions of low pop density
|
|
intrasexual selection
|
male to male or
female to female competition for opportunity to mate --leads to exaggerated secondary sexual characteristics (large size, aggressiveness) |
|
intersexual selection
|
differential attractiveness of individuals of one sex to another
**bright colors |
|
reproductive success depends on habitat selction
|
reinforces fact that we need to focus on habitats to preserve diversity
|
|
assigning species to either
-critically endangered -endanered -vulnerable REQUIRES one of the following: |
1)decline in ind #s of species
2)geographic area occupied & the # of pop 3)total # alive & # breeding 4)expected decline if current trends continue or habitat destruction continues 5)probability of species going extinct in certain # of yrs |
|
___ known species
|
1.4 million known species
--many beleive the actual # could be 10x that amt |
|
gradient of increasing species richness
|
from poles to equator
|
|
tropical rain forest contribution to species diversity
|
only cover 7% of land surface
more than 1/2 of all known species in these ecosystems |
|
topographic variation of species diversity
|
topographic variation (ridges, valleys)
support higher amt of diveristy than flatter areas in same region |
|
endemic species
|
restricted to certain habitat
|
|
hotspots
|
norman myers
-regions exhibiting high species richness and endemism -unusually high diversity BASED ON: 1)overall diversity of region 2)significance of impact from human activities -25 regions designated as hotspots by IUCN -contain 44% of all plant species -35% of all terrestrial vertebrate species -ONLY 1.4% of planets land area |
|
International Union for conservation of Nature
(IUCN) |
developed quantitative classification based on probability extinction
(demographic stochasticity & probability of extinction) |
|
Minimum Viable Population
(MVP) |
Shaffer
defined # of ind necessary to ensure long-term survival of species DEFINED AS: -the smallest isolated pop having 99% chance of remaining for 1000 yrs despite variations (below) -large enough to cope with chance variations in demographic processes (B&D), enviro changes, genetic drift, & catastophes -MVP dependent on life history of species & ability of ind to disperse amoung habitat patches |
|
Minimum Dynamic Area
(MDA) |
area required to support the MVP
-classification begins w/home range requirement |
|
"capture, relocation, release"
|
sometimes avoiding extinction requires establishing new pops thru transplants & reintroductions
|
|
larger areas contian greater # of species than small
|
-more heterogenous
--encompasses greater variety of habitats -provides greater probability that species can find another area of suitable habitat if something happens -some species require larger areas for basic needs --larger organisms have greater home ranges |
|
advantages to several small
rather than single large |
-once an area is larger than certain size the number of new species added w/each successive increase in area declines
-network of smaller areas positioned over larger region can include greater variety of habitat types and less suceptible to single catastophic eents |
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restoration ecology
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human intervention
restoring natural communities affected by human activities restoring ecosystem closest to original conditions prior to disturbance thru application of ecologic principles |
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economic argument to preserve biodiversity
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products come from orgnaisms
food drugs rubber, solvents paper, cotton, leather |
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evolutionary argument to preserve biodiversity
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processes of mutation, mixing of genetic info, & natural selection
give rise to new species all species eventually go extinct (some fade into extinction after giving rise to new species] --the mass extinction of modern day species limits the potential evolution of species diversity in the future |
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etical argument to preserve biodiversity
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humans are only one of millions of species inhabiting earth
to what degree will we allow human activities to continue to result in such a high rate of extinction? decrease in biodiversity? |
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ubiquitous
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a species w/ geographically widespread distribution
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a species' susceptability to extinction
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1)endemic
-loss of habitat in that one geographic region = complete loss of habitat 2)small metapopulations (one or few local pops) -more vulnerable to chance factors or habitat destruction 3)seasonal migration -depend on 2+ habitats -any one destroyed = extinction 4)specialized habitat requirements -specialized habitats often scattered and rare 5)species requiring large home range -habitat fragmentation 6)hunting / collecting or species that "threaten" human activity / human lives |
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"critically endangered species"
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50+% probability of extinction
within 10 yrs or 3 generations |
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"endangered species"
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20% probability of extinction
within 20 yrs or 5 generations |
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"vulnerable species"
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10+% probability of extinction
within 100 yrs |
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allelomimetic
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ex. flocking, schools
can confuse a predator |
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natural limits to pop growth
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-enviro not constant
-resources limited -as density increases, demand for resources increases -shrinking resources can increase mortality &/or decrease fecundity |
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logistic model of pop growth
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pop growth including B & D rate, & carrying capacity (K)
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carrying capacity suggests
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negative feedback between pop increase & resource availability
*density dependence* |
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density dependence
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influence pop in proportion to size
-regulates growth -function by slowing rate of increase |
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density independent
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influences w/o regard to number of individuals
(flood wiping out entire pop, whether 5 or 500 |
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intraspecific competition
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competition amoung individuals of the same species
(as long as availability doesn't impede survival, growth & reproduction.. no competition exists) **function as density-dependent** |
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2 kinds of competition
occur when resources are limited |
1)scramble competition
2)contest competition *normally only one type exhibited for a species (or at least during a given time of species life) |
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scramble competition
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-when growth and reproduction are depressed equally accross individuals in a pop
as intensity of competition increases -can lead to all individuals receiving insufficient resources = local extinction |
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contest competition
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-when some individuals claim enough resources while denying others a share
-can lead to only fraction of pop suffering (the unsuccessful ones) --successful ind sustain pop |
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exploitation
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ind respond to level of resource availability that is depressed by presence & consumption of other ind in the pop
*tree taking up water decreases remaining water in soil for other trees |
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interference
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ind interact directly preventing others from occupying habitat or accessing resources w/i it
*birds actively defend nest |
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"self-thinning"
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the progressive decline in density & increase in biomass of remaining ind's
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desity-dependent
self regulating factors |
-reduced fecundity
(when don't gain weight bc of high density -- not fertile) -high density = stressful (stress can supress growth & reproductive functions) -dispersal (to avoid stress some animals disperse) -social behavior -territoriality (defense of terriotory) (total area avail / size of territory = how many terr owners it can support |
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increasing CO2 in the atmosphere
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*greenhouse gas*
-due to fossil fuel combustion & clearing land for agriculture -plants respond w/ higher photosynthesis & partial closure of stomata --increase h2o use efficiency |
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global climate change
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could raise global mean temp by 1.4*C - 5.8*C by 2100
-not uniform -distribution/abundance will shift -rise in sea level -decrease in crop production somewhat offset by increase photsynthesis rates -mortality rates of humans raise due to heat related deaths ***to understand we must look at earth as a single, complex system*** |
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yield
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amt of resource (ie tree biomass) harvested per unit time
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rotation period
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after harvest the period of time required for new (trees) to grow the amt of resource to same level again
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sustained yeild
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*goal*
to have a similar yield at each harvest |
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swidden agriculture
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shifting cultivation
trees cut down and burned to clear land for planting **results in decline in productivity with each successive crop**` |
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sustainable agriculture
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maintaining agriculture production while minimizing enviro impacts
*reduce soil erosion, reduce use of fertilizers, pesticides* |
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clear cutting
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remmoval of forest and reversion to early stage of succession
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seed tree /
shelterwood system |
method of regenerating new stand by removing all trees except for a number of seed bearing trees
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selection cutting
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mature single trees or scattered groups are removed
--problem-- trails / roads needed |
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externalities
*econ concept* |
when actions of one ind affect another ind's well being but the releveant costs are not reflected anywhere in the market price
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rescue effect
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immigration maintining a local population that would otherwise go extinct
*as long as some migration occurs no extinction* |
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asynchronous dynamics
factor in persisting metapopulation |
-chance of extinction completely independent in each local pop
--decreased probability of metapop extinction |
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decreased ability of dispersal can be due to
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isolated habitats
low fecundity -asexual plants produce thru ramets and reduce dispersal ability -smaller organisms |
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4 levels of hierarchle spatial groups
defining a population *by garton* |
1)LOCAL POPULATION
-smallest -ideally distributed continuously 2)METAPOPULATION -collection of local pops close in proximity --dispersing ind can colonize empty patches that resulted from local pop extinction 3)SUBSPECIES -collection of metapop's in geographic region -metapops can be physically isolated by unsuitable habitats over large areas -rare dispersal --some gene flow 4)COLLECTION OF SUBSPECIES encompassing entire distribution / geographic range of species |
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patterns of dispersion can be sociobiological
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territory
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3 forms of peck order
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hierarchical
linear *most efficient* circular |
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warning calls of prairie dogs
ex of? |
altruism
**altruism is increasing fitness by taking care of relatives (who have your genes!) |
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biodiversity comes from
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organic evolution
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